In the past, there have been two separate systems in two separate machines for integrated circuit singulation based on wafer thickness and material. One is mechanical cutter dicing and the other is laser dicing. These techniques are typically employed in the end stages of integrated circuit fabrication when singulation of the integrated circuit chip is desired from the wafer in which it is formed. The thus formed integrated circuit chips are then placed within devices such as cellphones, videocameras, portable music players, microwaves, computers, etc.
Currently the industry uses mechanical cutting with a high precision circular cutter to singulate individual chips from a wafer. Older mechanical cutting methods employed a 50% cut through method followed by a breaking process, but this method is no longer acceptable for ULSI devices. Present day mechanical cutting methods use a 90 to 100% cut through technique, but this technique is still subject to substantial chipping, cracking, silicon dust production and corrosion.
Industry also currently uses laser dicing to singulate individual chips from a wafer. Laser dicing provides good quality dicing for thin wafers, low-k dielectrics, adhesives and copper wafers. Although laser dicing reduces some of the mechanical stresses introduced by mechanical cutting, it is privy to localized heating defects. Localized heating can cause unwanted melting of some materials, thereby causing reflow, as well as unwanted diffusion of some mobile ionic contaminants. The unwanted reflow and unwanted diffusion can lead to device failure due to short-circuiting. Additionally, laser dicing is unable to cut thick wafers efficiently, and consequently, the units per hour processed by laser dicing is inadequate for high throughput production processes.
Thus, despite recent developments in semiconductor dicing techniques, a need still remains for improved singulation techniques that will produce a high yield at the die/chip separation phase.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.